Author's note: these pages were written some years ago. I am not planning to update them. For a more current coverage, see the Palaeos website (to which many links on these pages point to anyway. More info here

Vulcanodon is the most primitive known sauropod dinosaur, and
retains a number of prosauropod features.
Yet some of the characteristics of the skeleton, such as the pubis,
are anatomically more advanced than in larger and later sauropods like
Barapasaurus. This is a good example
of what is called "mosaic" evolution, the presence of both primitive and
advanced characteristics within transitional organisms (Archaeopteryx
is a good example of this, displaying both theropod ("prmitive") and bird
('advanced") characteristics.)

Somewhat contradictory dates have been given for the "Vulcanodon Beds".
Although reported from the earliest Jurassic, close to the Triassic boundary
(i.e. early Hettangian),
pollen analysis indicates a date no older than the Sinemurian, and possibly
younger [Paul E. Olsen & H-D Sues, "The Triassic-Jurassic tetrapod
transition", p.329 n.; in The Beginning of the Age of Dinosaurs,
ed. K.Padian]. I have tentatively dated Vulcanodon as Sinemurian.
In any case it seems that the Vulcanodontids and their descendents quickly
supplanted the Plateosaurs as large terrestrial herbivores, althogh smaller
prosauropods continued up until the Toarcian.

Reference is made to a sauropod dinosaur from the Wudin basin
in Yunnan, China. Although the horizon is thought equivalent to the
adjacent famous prosauropod-dominated Lower Lufeng formation (Hettangian),
there is no evidence for sauropods in the Lufeng beds [A.L.Sun and K.H.Cui,
"The Lower Lufeng Saurischian fauna", p.278, and Peter M. Galton, "Herbivorous
adaptions of dinosaurs, p.208; in The Beginning of the Age of Dinosaurs,
ed. K.Padian] and it is likely that Kunmingosaurus and Chinshakiangosaurus
comes from a later period, perhaps close in time to Vulcanodon.
A Sinemurian
age is tentatively suggested. (The Dinosauricon entry for Chinshakiangosaurus
has the date as late Jurassic, but this is most probably an error.)

Damalosaurus spp. Zhao 1983
Yet another brief reference to a far-east Asian early Jurassic
sauropod, this one from Tibet [Peter M. Galton, "Herbivorous adaptions
of dinosaurs, p.208; in The Beginning of the Age of Dinosaurs, ed.
K.Padian]. As the SinemurianScelidosaurus also has been supposedly reported from Tibet
[unfortunately my only reference here is David Lambert's Field Guide
to Dinosaurs], these two may possibly have been contemporary.
Mike Keesey [Damalasaurus
page] gives the age as Middle Jurassic, the locality as China
(tsk tsk!), and suggests this genus may possibly be a Brachiosaur.
Of course it might also be a distinct lineage of primitive sauropod.
D. laticostalis Zhao, 1985D. magnusBoth these species are now considered invalid [nomen
nudum].

Ohmdenosaurus liasicus Wild, 1978
Posidonienschiefer, Baden-Wurttemberg, GermanyAge: Middle Toarcian Limb bone Estimated overall length: 4 metresThis very small, primitive sauropod is known only from a single
limb bone, once thought to belong to a plesiosaur.
Although classified under the family Vulcanodontidae it may instead belong
to a distinct group, which might be called family Ohmdenosauridae.
It had no clear descendents, and may have been one of the many types of
dinosaur that were wiped out by the terminal Toarcian extinction event.

The first of the really big sauropods, Baraposaurus equalled
in size the giants of the later Jurassic. In structure however it
was much more primitive, resembling Vulcanodon
in many features of the skeleton. As befits its transitional nature,
it is sometimes included under the Vulcanodontidae, sometimes under the
Cetiosauridae, and sometimes in its own family. Barapasaurus is another
example of "mosaic evolution" among transitional forms. According
to the Argentine palaeontologist Jose Bonaparte the dorsal vertebrae of
Barapasaurus are of the standard Cetiosaur grade, with a tall neural
arch and zygapophyses far above the neural canal; much more advanced the
vertebrae of Vulcanodon.

references:Jose
Bonaparte, 1986, "The early radiation and phylogenetic relationships of
the Jurassic sauropod dinosaurs, based on vertebral anatomy", in The
Beginning of the Age of Dinosaurs, ed. K.Padian]